1. Field of the Invention
The present invention relates to an olefin polymerization catalyst prepared by using a modified aluminumoxy compound as one component and a process for producing an olefin polymer with said catalyst.
2. Description of Related Arts
Many processes for producing an olefin polymer using a metallocene complex have been already reported. For example, a process for producing an olefin polymer, using a metallocene complex and an aluminoxane is reported in JP58-19306A. However, this process using bis(xcex75-cyclopentadienyl)zirconium dichloride and methylaluminoxane has insufficient activity from the industrial viewpoint, and the molecular weight of the olefin polymer obtained was low.
In order to solve these problems, many proposals on the improvement of an aluminum oxy compound have been made. For example, polymerization processes using a metallocene, an aluminum oxy compound and phenols having a bulky substituent are disclosed in JP6-136053A and JP9-291107A. A catalyst system using a metallocene, an aluminum oxy compound and a monoalkyl bis(aryloxy)aluminum is disclosed in JP-A-10-36423.
An olefin polymerization process using zirconocene and an aluminum oxy compound having an electron withdrawing group or a group which contains an electron withdrawing group is disclosed in JP-A-06-329714. Further, a polymerization process using zirconocene and aryloxyaluminoxane having an electron withdrawing group is disclosed in WO94-10180.
However, the processes described above are not necessarily sufficient in the catalytic activity, and therefore the improvement of the catalyst activity has been desired.
An objective of the present invention is to provide a highly active olefin polymerization catalyst using a metallocene-based transition metal compound and a process for producing an olefin polymer with said catalyst.
That is, the present invention relates to an olefin polymerization catalyst prepared by contacting (A) with (B) described below, and further to an olefin polymerization catalyst prepared by contacting (C), (D) or (C) and (D) in addition to said (A) and (B), as components described below:
(A) a transition metal compound selected from the group consisting of transition compounds represented by the general formulas (I), (II) and (III); 
xe2x80x83wherein, in the general formula (I), (II) or (III), M represents a transition metal atom of the Group IV of the Periodic Table of the Elements; A represents an atom of the Group XVI of the Periodic Table of the Elements; J represents an atom of the Group XIV of the Periodic Table of the Elements; Cp represents a group having a cyclopentadiene type anion skeleton; each of X1, R1, R2, R3, R4, R5 and R6 independently represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, a substituted silyl group, an alkoxy group, an aralkyloxy group, an aryloxy group, a di-substituted amino group, an alkylthio group, an aralkylthio group, an arylthio group, an alkylseleno group, an aralkylseleno group or arylseleno group; X2 represents an atom of Group XVI of the Periodic Table of the Elements; R1, R2, R3, R4, R5 and R6 may be optionally combined with each other to form a ring; and in the general formula (II) or (III), two of M, A, J, Cp, X1, X2, R1, R2, R3, R4, R5 and R6 may be respectively the same or different.),
(B) Modified aluminum oxy compound
a modified aluminum oxy compound (B) obtained by reacting (B1) with (B2) described below;
(B1) an aluminum oxy compound, and
(B2) a compound having a hydroxyl group.
(C) at least one aluminum compound selected from the following (C1) to (C3);
(C1) an organoaluminum compound represented by the general formula E1aAlZ3xe2x88x92a,
(C2) a cyclic aluminoxane having a structure represented by the general formula {xe2x80x94Al(E2)xe2x80x94Oxe2x80x94}b, and
(C3) a linear aluminoxane having a structure represented by the general formula E3{xe2x80x94Al(E3)xe2x80x94Oxe2x80x94}cAlE32 (wherein E1, E2 and E3 respectively represents a hydrocarbon group, all of E1, E2 and E3 may be the same or different, Z represents a hydrogen atom or a halogen atom, and all of Z may be the same or different, a represents a numeral satisfying 0 less than axe2x89xa63, b represents an integer of not less than 2, and c represents an integer of not less than 1); and
(D) any one of boron compounds of (D1) to (D3) described below:
(D1) a boron compound represented by the general formula BQ1Q2Q3;
(D2) a boron compound represented by the general formula G+(BQ1Q2Q3Q4)xe2x88x92; and
(D3) a boron compound represented by the general formula (Lxe2x80x94H)+(BQ1Q2Q3Q4)xe2x88x92 (wherein B is a boron atom in the trivalent valence state; Q1 to Q4 are a halogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a substituted silyl group, an alkoxy group or a di-substituted amino group which may be the same or different; G+ is an inorganic or organic cation; L is a neutral Lewis base; and (Lxe2x80x94H)+ is a Brxc3x8nsted acid).
Further, the present invention relates to a process for producing an olefin polymer which comprises polymerizing an olefin with the olefin polymerization catalyst described above.